Diesel fuel



i increase the tane numbers of the fuel.

the various peroxides used in the past for this Fatented June 12, 1945 presuppose William E. Vaughan and Frederick E. Rust,

Berkeley, Calif assignors to Shell Development Company, San Francisco, @alii a corporation of Delaware r No Drawing. Application February 8, 1943,

Serial No. 475,215

. 11 claims. This invention relates to Diesel fuels containing a knock depressor, and more'particularly deals with such fuels containing a small amount of a peroxide of a branched chain aliphatic hydrocarbon.

, It is known that hydrocarbon peroxides and other organic peroxides have the property, when dissolved in hydrocarbon Diesel fuels, of acting as ignition accelerators 'oi the latter, i. e., they However,

purpose have had various disadvantages, among them being particularly their explosibility. For example, tetraline peroxide, ketone peroxides, etc., are all highly explosive, and their handling diluted with inert material. Other Diesel knock depressors, such as alkyl nitrates or dialkyl polysulfides, are either corrosive or produce corrosive products upon combustion or bothr In contrast, the peroxides of this invention are substantlally non-corrosive, stable and substantially non-explosive, even in highly concentrated state. On ignition, they burn with a sooty smooth flame, and when dropped on ahot plate maintained at 250 0., they merely vaporize, but fail to explode. I

It is thus a purpose of this invention to produce Diesel fuel oils of increased cetane numbers, which are safe in manufacturing and handling. Another purpose is to provide a cheap and effec-' tive means for raising the cetane numbers of Diesel fuels.

Our invention comprises hydrocarbon Diesel fuels of relatively high octane numbers containing an added small amount, i. e., about /;%-5%, and preferably 1%-3%, of peroxide of a hydrocarbon having an aliphatic tertiary carbon atom, wherein the percxy radical connects two tertiary carbon atoms. y

The peroxides used in this invention are produced by slow, non-explosive. oxidation of a hydrocarbon containing at least one tertiary carbon atom of aliphatic character in the presence 01a hydrogen halide, particularly hydrogen bromide, or a compound capable of yielding such hydrogen halide under operating conditions.

wherein each R represents a like or-difierent islexceedingly dangerous unless they are highly cal, two of which may together form an alicyclic ring, and which radicals may be further substituted, for instance, by the presence of one or more halogen, nitrogen or oxygen atoms which are attached to one or more of the carbon atoms of such radicals. A preferred class of organic compounds which may be used as a'starting material comprises the saturated aliphatic hydrocarbons containing at least one tertiary carbon atom. Specific examples of the latter are isobutane, 2-methyl butane, 2-ethy1 butane,

Z-methyl pentane', 'S-methyl pentane, 2,3-dimethyl butane, ZA-dimethJII butane and their homologues, preferably having not more than about 12 carbon atoms.

in the neighborhood oi around 150 C., temperatures between 100 to about 250 C. being normally applicable. 1

The oxidation may be efiected in the liquid or vapor phase or both, vapor phase being preferred. As a result of the oxidation, some acids, ketones and aldehydes are produced; however, a: substantial portion of the reaction product consists of the peroxides employed in this invention, which, it is believed, may be represented by the formula:

wherein each R again represents a like or difie'rent hydrocarbon radical which may or may not be further substituted. Preferred compounds carbon atoms. These compounds are waterwhite, oil-soluble, water-insoluble liquids having ,of the polymers, or resulting from the alkylation of isobutane with butylenes, or other alkylate gasolines having relatively wide boiling ranges.

0 Also mixtures of hydrocarbons containing an aliphatic tertiary carbon atom with other hydro.-

carbons may be oxidized to produce the peroxides useful in accordance with this invention.

If desired, the Diesel fuels may contain addialkyl, aryl, aralkyl, alicyclic or heterocyclic raditional additives, such as anti-oxidants,.e. e.,

The temperature of the oxidation is normallyare the symmetrical, saturated, di(tertiary alkyl) peroxides having not more than about 24 various alkyl phenols such as xylenols, trimethyl phenol, 2,4-dimethyl-6-tertiary butyl phenol, 4-methyl-2,6-ditertiary butyl phenol, etc; aromatic amines, preferably secondary aromatic amines, such as N ,N' dibutyl phenylene diainine, diphenylamine, phenyl alpha naphthylamine, alpha alpha, alpha beta, or beta beta.

dinaphthylamines; amino phenols, such as benzyi' para amino phenol, etc.; anti-corrosive agents such as dicarboxylic acids having at least 16 carbon atoms, e. g., alkyl succinic acids; pour point reducers, viscosity or viscosity index improvers, wear reducers, such as carbamic acid esters, allophanic acid esters, etc.

Moreover, other Diesel knock' depressors, such To a California Diesel fuel having a cetane number of 40.5 was added 1% of isobutane peroxide prepared by the slow combustion described above. was thereby raised to slightly above 56.

We claim as our invention:

1. A Diesel fuel of improved cetane number comprising a predominant amount of a hydrocarbon Diesel fuel and a cetane improving amount of a peroxide of a hydrocarbon having at least one aliphatic tertiary carbon atom, the peroxy radical in said peroxide connecting two tertiarycarbon atoms.

2. A Diesel fuel of improved cetane number comprisinga predominant amount of a hydrocarbon Diesel fuel and a cetane improving amount of a peroxide of a chlorinated hydrocarbon having at least one aliphatic tertiary carbon atom, the peroxy radical in said peroxide connecting two tertiary carbon atoms.

3. A Diesel fuel of improved cetane number comprising a predominant amount of a hydro-' carbon Diesel fuel containing about A;%5% of a peroxide of a hydrocarbon having atleast one aliphatic tertiary carbon atom, the peroxy radical in said peroxide connecting two tertiary carbon atoms.

4. A Diesel fuel of improved cetane number comprising a predominant amount of a hydrocarbon Diesel fuel containing about 1%-3% of a peroxide of a hydrocarbon having at least one aliphatic tertiary carbon atom, the peroxy radical in said peroxide connecting two tertiary carbon atoms. a

5. A Diesel fuel of improved cetane number comprising a predominant amount of a hydro- The cetane number of the fuel carbon Diesel fuel and a cetane improving amount of a peroxide of a hydrocarbon having not more than 12 carbon atoms and at least one aliphatic tertiary carbon atom, the peroxy radical in said peroxide connecting two tertiary carbon atoms.

6. A Diesel fuel of improved cetane number comprising a predominant amount of a hydrocarbon Diesel fuel and a cetane improving amount of a peroxide of compounds having the formula wherein the several R's represent hydrocarbon radicals, the peroxy radical of said peroxide connecting two of said compounds through their tertiary carbon atoms.

7. A Diesel fuel of improved cetane number comprising a predominant amount of a hydrocarbon Diesel fuel and a cetane improving amount of a peroxide obtained by slow oxidation of a hydrocarbon containing at least one aliphatic tertiary carbon atom.

8. A Diesel fuel of improved cetane number comprising a predominant amount of a hydrocarbon Diesel fuel and a cetane improving amount of'a peroxide having the formula wherein the several R's represent hydrocarbon radicals.

9. A Diesel fuel of improved cetane number comprising a predominant amount of a hydrocarbon Diesel fuel and a cetane improving amount of a symmetrical peroxide having not more than 24 carbon atoms and the formula wherein the several Rs represent hydrocarbon radicals.

10. A Diesel fuel of improvedcetane number comprising a predominant amount of a hydrocarbon Diesel fuel oil and a cetane improving amount of a di-isobutane peroxide wherein the peroxy radical connects two tertiary carbon radicals.

.11. A Diesel fuel of improved cetane number comprising a predominant amount of a hydrocarbon Diesel fuel oil and a cetane improving amount of di-isopentane peroxide wherein the -peroxy radical connects two tertiary carbon radicals.

WILLIAM E. VAUGHAN. FREDERICK F. RUST.

CERTIFICATE OE CORREKJT'IOIL- June 12, 19115.

Patent No. 2375mm.

WILLIAM E. VAUGHAN, ET AL.

s hereby certified that error appears in the printed specification of the above mnnbered patent requiring correction as follows: Page 1, first 10, for "tens" read cetane--; and that the sa read with this correction therein that the same may n the Patent Office.

column, line ent should be to the record of the case i Signed and sealed this 2 A. D'. l91L5.

5rd day of October,

Leslie Frazer sioner of Patents.

(Seal) First Assistant Commie 

